Drop out fuse having motivating means and slidably mounted on one of its terminals



Oct. 13, 1964 T. A. BURDESHAW 3,

DROP OUT FUSE HAVING MOTIVATING MEANS AND SLIDABLY MOUNTED on ONE OF ms TERMINALS Filed July 17, 1961 Sheets-Sheet 1 IN VEN TOR.

THOMAS A. BURDESHAW FIG. 4.

AT TORN EY Oct. 13, 1964 'r. A. BURDESHAW 3,

DROP ou'r FUSE HAVING MOTIVATING MEANS AND SLIDABLY MOUNTED ON ONE OF ITS TERMINALS Filed July 17. 1961 2 Sheets-Sheet 2 mmvrox THOMAS A. BURDESHAW ATTORNEY United States Patent Office 3,153,126 Patented Oct. 13, 1964 3,153,126 DRGP OUT FUSE HAVING MOTIVATING MEANS AND SLIDABLY MOUNTED ON ONE @F ITS TERMHNALS Thomas A. Rurdeshaw, Hampton, Ga, assignor to Southern States Inc., a corporation of Georgia Filed July 17, 1961, 'Ser. No. 124,671 Claims. (Cl. 200-114) This invention relates to an electric fuse and more particularly to a fuse of a type in which a pair of spaced insulated terminals are interconnected by a fuse tube which is disposed substantially horizontally during its circuit closed position and which is provided with releasable motivating means arranged to swing the tube upward into a substantially vertical position upon the occurrence of a circuit interrupting operation.

For certain applications of electric fuses it is desirable to interconnect a fuse with an electric switch and frequently space requirements are such that it is not feasible to rely on gravity as a means for disconnecting one end of a fuse holder from its associated terminal when a circuit interrupting operation takes place. Hence it is necessary to provide motivating means which perform the circuit isolating operation by swinging the fuse holder and its fuse link about one of the terminals of the fuse.

A principal object of this invention is to provide an improved power fuse in which motivating means for swinging the fuse tube to the open circuit position is provided and which motivating means responds to rupture and separation of the fuse link.

Theinvention in one form as applied to a power fuse comprises a pair of terminals mounted in insulated spaced relation, a support element pivotally mounted on one of the terminals, a fuse tube slidably mounted on the support element and normally in engagement with the other terminal, a spring arranged to swing the support element and its associated fuse tube away from the other terminal upon rupture of the fuse link, and restraining means normally held in a normal position by the fuse link for normally holding the fuse tube in its normal position relative to the support element and to the other terminal.

For a better understanding of the invention reference may be had to the following detailed description taken in conjunction with the accompanying drawings in which FIG. 1 is a side View of a power fuse embodying the invention; FIG. 2 is a view taken along the line 2-2 indicated in FIG. 1; FIG. 3 is a side view with certain portions of the structure cut away taken along the line designated 3-3 in FIG. 2 and depicting the hinge end of the fuse tube; FIG. 4 is an enlarged side view of the left hand end of the structure depicted in FIG. 1; FIG; 5 is a fragmentary view of a portion of the structure depicted in FiG. 3, but with parts removed for clarity; FIG. 6 is a view similar to FIG. 3 but which shows the parts in the positions which they occupy immediately following rupture of the fuse link and after the fuse tube has been moved out of its normal position relative to the support element; FIG. 7 is a fragmentary view similar to FIG. 5 but which shows the parts in the positions they occupy after rupture of the, fuse link; FIG. 8 is a schematic view of a part of a fuse tube, and a schematically represented support element, and restraining means arranged normally to hold the support element and fuse tube in their normal position; FIG. 9 is a view similar to FIG. 8 but which depicts the fuse tube in the position which it occupies after it is moved out of its normal position from the support element by a biasing element; and in which FIG. 10 is a view similar to FIG. 3 of the hinge end of the power fuse after themotivating means has swung the fuse holder including the fuse tube and associated parts into its vertical or open circuit position.

With reference to FIG. 1, the numeral 1 is used to designate a switch base upon which fixed insulators 2 and 3 are mounted by means of bolts 4 and 5. A terminal element generally designated by the numeral 6 is securely affixed atop insulator 2 and is provided with a terminal pad 7. Aflixed atop the insulator 3 is a terminal element generally designated by the numeral 8 to which is secured a fixed terminal pad 9. Secured atop the terminal element 6 adjacent terminal pad '7 is a cradle lb of known construction the purpose of which is to receive the right hand end of the fuse link upon rupture thereof during circuit interrupting operation. .Cradle 10 comprises a pair of arcurate elements between which a plurality of spaced rod-like devices are supported. A similarcradle 11 is mounted atop terminal element 8.

Cradle 11 is for the purpose of receving the fuse link button head and a pressure relieving disc which may be constructed in accordance with Patent No. 2,903,538, granted September 8, 1959, and assigned to the assignee of this invention.

The fuse holder as'shown in the drawings comprises an outer insulating tube 12 to each end of which tube hardware is afiixed in known manner. As shown in the drawings, a closure element 13 is disposed at the left hand end of the fuse tube and is afiixed to the hardware on that end of the tube and a hook stick engaging holding device 14 is affixed to the fuse hardware and is for the purpose of enabling an operator to manipulate the fuse holder comprising tube 12 and parts associated therewith by means of an ordinary hook stick. Releasable element 13 and switch hook engaging element 14 are mounted on the fuse terminal hardware 15 which is secured by pins 16 to the insulating tube 12 as best shown in FIG. 4. The hardware 15 is interposed between a pair of spaced elements 17 and 18 and an outwardly extending L-shaped contact latch element 19 is formed integrally with the depicted in the closed position in FIG. 4 over rides the outwardly, extending arm of the latch element 19 so as to hold the tube in the closed position.

- For the purpose of insuring adequate contact pressure between the lower part of contact latch 19 and terminal element 8, a magnetic loop 23 is securely affixed to the terminal element 8 along the lower prong 23A thereof. The upper prong designated by the numeral 23B is biased by a compressional spring 24 upwardly so as to afford a yieldable contact surface for engagement by the lower surface of the contact latch 19.

The current path through the structure depicted in FIG. 4 comprises terminal pad 9, the body portion of terminal element 8, conducting loop 23, contact latch19, and terminal 15. The button head of the fuse link which is not depicted in the drawings is held in place underneath the pressure relieving closure element 13. Of course current is conducted along the inside of the insulating fuse tube 12 by the fuse link which, as depicted in FIG. 3, is designated by the numeral 25 and which is connected by a bolt 26 to fuse tube support element designated generally by the numeral 27. p

Terminal element 27 is pivotally mounted by pin 28 which is disposed in jaws formedin the prongs of the U-shaped support element 29 bestshown in FIG. 2. It will be understood that the U-shaped bracket 29 is securely mounted atop the terminal element 6 and forms a part thereof.

For the purpose of making good electrical contact between the support element 27 and the terminal element 6 a pair of loop contacts 3% and 31 are arranged so that their lower portions are securely afiixed by bolts 32 and 33 respectively to the inwardly extending parts of the bracket 29. These loop elements 3t) and 31 are respectively provided with compressional springs 34 and 35 which bias the upper portions 36 and 37 of the loop contacts into good contact engagement with the lower part of each side of the support element 27.

The circuit from the fuse link 25 and the bolt 26 eX- tends through the support element 27, the loop elements 3d and 31, the U-shaped support bracket 29, terminal element 6, and terminal pad '7.

For the purpose of imparting swinging movement to the fuse tube 12 and parts associated therewith about the pin 28 as a pivot, motivating means in the form of torsional spring 38 is provided and is disposed within an outer housing 39 mounted by means of bolts 4t? to one side of the U-shaped bracket 29. Engagement between the torsional spring 38 and support element 27' is via the elongated prod at best shown in FIG. 3. The prod 41 forms an integral part of terminal element 27. This prod cooperates with the left hand end of spring 38 in known manner and such cooperation is not depicted in the drawing. Suffice it to say that with prod 41 inserted into an appropriate slot and with the fuse holder in the vertical position depicted in FIG. ll), rotation of the fuse tube 12 and parts associated therewith in a counterclockwise direction charges the spring Of course it will be understood that rotation of fuse tube 12 in a counterclockwise direction to the closed position allows the latching surface 19 to ride under the yieldably mounted latch portion 21B of the latch 21. In this manner the fuse tube is retained against clockwise rotation due to the bias of. motivating means 3 3.

In order for the motivating means 33 to swing the fuse tube 12 in a clockwise direction about the 2? upon circuit interruption and separation of the ends of the fuse link 95, the latch element must move horizontally toward the right as viewed in the drawings so as to move out from under the latching portion 21B of the latch 21. In order to accommodate such movement, the fuse tube 12 is slidably mounted relative to the support element 27 and is normally maintained in its normal position depicted in FIG. 4 by restraining means in the form of a pair of toggle links 42 and d3. Toggle link 42 is pivoted at pin 44 to metallic collar securely affixed as by a pin 46 to the right hand end of the fuse tube 12. Link is secured by pin d7 to one end of the link d3. Link 43 is pivoted at pin 48 to the support element 27. As is best shown in FIG. 5 the links 42 and 43 are maintained in their normal positions of generally parallel relationship by means of the fuse link 25. It will be observed from FIG. 5 that a pair of prongs l9 and 5d form a part of link 43 and are arranged so as to engage the fuse link 25.

For the purpose of slidably interrelating a part of the collar 45 with the support element 27 by a low friction relationship, rollers designated by the numerals 5f, 52, and 53; are rotatably mounted on the part of the support element 2'7 designated by the numeral it will be understood that there are four rollers altogether and that one of the rollers is not shown in any of the draw ings, such roller being disposed opposite the roller 52.

Afiixed to the left hand end of the support element 27 is a downwardly depending pad 55. Mounted for movement with the collar 45 is a housing as secured by bolts 5'7 underneath the portion 5 of the support element 27. Thus the support element 2'7 forms one part of a telescopically related structure comprising the part 5 of support 27 and the housing 56 secured to the collar d5. As is best shown in FIG. 3 these telescopically related parts are biased for movement in a longitudinal direction by a compressional spring designated in the drawings by the numeral 59 From the description thus far it will be understood that when the fuse link is ruptured due to an overcurrent, for example, the tension thereof is relaxed so that the fuse link moves from the condition depicted in FIG. 5 to that depicted in F168. 6 and 7. Thereafter spring 59, bearing on the right hand surface 5A of the housing 56 and on the portion 55 of support element 2?, drives the fuse tube 12 towards the right. Thereafter the latch 19 is released and the motivating device 38 swings the support element 27 and the fuse tube 12 and parts associated therewith into the position depicted in FIG. 10. In this manner a visible indication of an open circuit condition is projected.

Opening movement of fuse tube 12 and associated parts is arrested in known manner by buffer While I have shown and described a particular embodiment of the invention 1 do not wish to be limited thereto and intend in the appended claims to cover all changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric fuse comprising a pair of terminals mounted in insulated spaced relation, a support element pivotall" mounted on one of said terminals, a fuse tube slidably mounted on said support element and normally in engagement with the other of said terminals, and motivating means arranged to swing said support element about its pivotal mounting on said one terminal thereby to swing said tube away from the other of said terminals, said motivating means being ineffective to swing said tube out of engagement with said otner terminal when said tube is in its normal position relative thereto and being effective to separate said fuse tube from said other terminal upon predetermined relative sliding movement between said tube and said support element.

2.. An electric fuse comprising a pair of terminals mounted in insulated spaced relation, a support element pivotally mounted on one of said terminals, a fuse tube slidably mounted on said support element and nor. sly in engagement with the other of said terminals, biasing means tending to slide said tube out of its normal position relative to said support element, releasable restraining means normally holding said tube in its normal position relative to said support element against the action of said biasing means, and motivating means arranged to swing said support element about its pivotal mounting on said one terminal thereby to swing said tube away from the other of said terminals, said motivating means being ineffective to swing said tube out of engagement with said other terminal when said tube is in its normal position relative thereto and being effective to separate said fuse tube from said other terminal upon predetermined relative sliding movement between said tube and said support element.

3. An electric fuse comprising a pair of terminals mounted in insulated spaced relation, a support element pivotally mounted on one of said terminals, a fuse tube slidably mounted on said support element and normally in engagement with the other of said terminals, a fusible element disposed within said tube, biasing means tending to slide said tube out of its normal position relative to said support element, releasable restraining means normally holding said tube in its normal position relative to said support element against the action of said biasing means, said restraining means being normally in engagement with a part of said fusible element and being held thereby in its normal position, said restraining means being released upon rupture and separation of said fusible element, and motivating means arranged to swing said support element about its pivotal mounting on said one terminal thereby to swing said tube away from the other of said terminals, said motivating means being inelfective to swing said tube out of engagement with said other terminal when said tube is in its normal position 5 relative thereto and being effective to separate said fuse tube from said other terminal upon predetermined relative sliding movement between said tube and said support element.

4. An electric fuse comprising a pair of terminals mounted in insulated spaced relation, a support element pivotally mounted on one of said terminals, a fuse tube slidably mounted on said support element and normally in engagement with the other of said terminals, a fusible element disposed within said tube, biasing means tending to slide said tube out of its normal position relative to said support element, releasable restraining means normally holding said tube in its normal position relative to said support element against the action of said biasing means, said restraining means including a pair of toggle links pivotally connected together, one of said toggle links being pivotally connected with said fuse tube and the other of said toggle links being pivotally connected with said support element.

5. An electric fuse comprising a pair of terminals mounted in insulated spaced relation, a support element pivotally mounted on one of said terminals, a fuse tube slidably mounted on said support element and normally in engagement with the other of said terminals, a fusible element disposed within said tube, biasing means tending to slide said tube out of its normal position relative to said support element, releasable restraining means normally holding said tube in its normal position relative to said support element against the action of said biasing means, said restraining means including a pair of toggle links pivotally connected together, one of said toggle links being pivotally connected With said fuse tube and the other of said toggle links being pivotally connected with said support element, said toggle links being normally held in generally parallel relation to each other by said fusible element and being biased away from their normal positions against the holding action of said fusible element.

References Cited by the Examiner UNITED STATES PATENTS 1,965,391 7/34 Pittman 200-114 2,668,209 2/54 Cooper an 200-114 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

1. AN ELECTRIC FUSE COMPRISING A PAIR OF TERMINALS MOUNTED IN INSULATED SPACED RELATION, A SUPPORT ELEMENT PIVOTALLY MOUNTED ON ONE OF SAID TERMINALS, A FUSE TUBE SLIDABLY MOUNTED ON SAID SUPPORT ELEMENT AND NORMALLY IN ENGAGEMENT WITH THE OTHER OF SAID TERMINALS, AND MOTIVATING MEANS ARRANGED TO SWING SAID SUPPORT ELEMENT ABOUT ITS PIVOTAL MOUNTING ON SAID ONE TERMINAL THEREBY TO SWING SAID TUBE AWAY FROM THE OTHER OF SAID TERMINALS, SAID MOTIVATING MEANS BEING INEFFECTIVE TO SWING SAID TUBE OUT OF ENGAGEMENT WITH SAID OTHER TERMINAL WHEN SAID TUBE IS IN ITS NORMAL POSITION RELATIVE THERETO AND BEING EFFECTIVE TO SEPARATE SAID FUSE TUBE FROM SAID OTHER TERMINAL UPON PREDETERMINED RELATIVE SLIDING MOVEMENT BETWEEN SAID TUBE AND SAID SUPPORT ELEMENT. 